Calculation for manual water top offs?

[Karen00]

Hello R2R folks,

I've been searching this forum and doing general Google searches but haven't found what I'm looking for regarding top offs (due to evaporation).

All of the posts I've read so far indicate knowing how much your tank evaporates so you know how much to replace which totally makes sense but what if you haven't been paying attention or it fluctuates on a daily basis (for whatever reason). My question is.... Is there a way to determine how much you need to add a based on your target parameters and your evaporated parameters? I guess a sub-question would be what parameters to look at? Ex: If calcium and alkalinity should be balanced then can you use these as the reference so if my target for Ca is "x" and my target for All is "y" and my new values after evaporation is Ca is "a" and Alk is "b" then is their a formal of how much RODI water to add to get back to x and y?

I thought this would be fairly simple and there would be a calculator for it but I can't seem to find one (or a calculation to use). Maybe it's not so easy and it's just best/easier to measure how much has been lost to know how much to replace (like putting a small mark on your tank)?

 

[Adamantium]

I think you’re over complicating things. If you don’t want/can’t afford an ATO yet, just put a line on the tank and fill back to that line.

I’d hiiiighly recommend an ATO, though. You can get them for as little as $70-80 these days, and it was one of the best “upgrades” I’ve ever made to my tank (I say “upgrade” because it’s really more of a necessity).

 

[WVNed]

You establish a running water level when your system is full with the correct salinity. Make a mark there. Then you add top off water to come back to that level.
No math required

 

[Karen00]

I think you’re over complicating things. If you don’t want/can’t afford an ATO yet, just put a line on the tank and fill back to that line.

I’d hiiiighly recommend an ATO, though. You can get them for as little as $70-80 these days, and it was one of the best “upgrades” I’ve ever made to my tank (I say “upgrade” because it’s really more of a necessity).

Thanks for this!! I figured putting a mark on the tank would be the easiest way to do this but wasn't sure if a calculation would be more precise (or would be better). I'm just starting to look at ATOs and I agree that's probably a good/inexpensive investment.

 

[Karen00]

You establish a running water level when your system is full with the correct salinity. Make a mark there. Then you add top off water to come back to that level.
No math required

Awesome thanks!! I'm so glad to know that this is perfectly acceptable. Sometimes the KIS method is the best after all. I'm looking at ATOs but wanted to be sure I had a way to do this correctly without one or the ATO fails, etc.

 

[Adamantium]

Thanks for this!! I figured putting a mark on the tank would be the easiest way to do this but wasn't sure if a calculation would be more precise (or would be better). I'm just starting to look at ATOs and I agree that's probably a good/inexpensive investment.

100% worthwhile. AutoAqua has a few options that have been great for me.

The reason there’s no calculation is because of all the variables. Humidity level in your home being the biggest one. Keeping a steady water level is all you need to do.

Good luck!

 

[Karen00]

100% worthwhile. AutoAqua has a few options that have been great for me.

The reason there’s no calculation is because of all the variables. Humidity level in your home being the biggest one. Keeping a steady water level is all you need to do.

Good luck!

Thank you for the ATO suggestion. I just started googling this subject but was getting a little overwhelmed by all of the different ones out there (like most of the equipment needed I suppose). Haha.

 

[Biglew11]

topping off evaporation is done to keep salinity stable. to keep other things in check we do water changes, and dosing(only if needed).

 

[Cell]

The problem with a calculation is your evaporation rate will change with the weather/seasons. Draw the water line with a marker and eventually you'll develop a pretty good feel for your evaporation rate.

 

[Karen00]

topping off evaporation is done to keep salinity stable. to keep other things in check we do water changes, and dosing(only if needed).

Yes, I knew about salinity and should have mentioned that. I was thinking of top offs in the context of a reef (FOWLR would only be affected by salinity).

Actually this does bring another question to mind... So I know evaporation concentrates salinity which is bad but does it also concentrate the other elements like Ca, Mg, etc making them a concern as well (for a reef) or do those go up with the evaporated water? I thought I read everything is left behind but maybe I'm wrong.

As per my question about a calculation for top-offs and now thinking of it in terms of salinity is there a calculation for freshwater to get your tank back to your desired salinity? I know putting a mark on the tank or using an ATO is the easiest. I'm just curious whether there is a way to calculate this (for salinity, nothing else).

 

[Karen00]

The problem with a calculation is your evaporation rate will change with the weather/seasons. Draw the water line with a marker and eventually you'll develop a pretty good feel for your evaporation rate.

Apparently I like to make things complicated. LOL I kept thinking putting a mark on my tank is just way too easy and I must be missing part of the secret sauce in water management. Apparently not... A mark on the tank is perfectly acceptable and will keep my tank's inhabitants happy! LOL

 

[terraincognita]

I didn't read anything. because I don't do stuff like calculations for this.

If you dont want to buy an ATO.

Easiest solution man is to MARK the water level with a marker or tape or something.

Then just re-fill it everyday to that level.

I don't stress about it too much.

Unless you have over 150G the evap should be less than a gallon a day, which in that size is not causing any huge salinity swings.

Just dont let it go on too long before checking.

Exhibit A.

 

[WVNed]

Salinity is set by mixing a measured amount of salt in a particular amount of water. The salt never leaves the tank but the water evaporates. Adding back new water to the same volume brings the water back to the same salinity.
How fast the water evaporates depends on room temperature and humidity and changes from summer to winter.

None of the other components of your salt mix like Ca or MG will evaporate either but their levels will change because they are used by animals in your tank and other factors.

 

[Karen00]

I didn't read anything. because I don't do stuff like calculations for this.

If you dont want to buy an ATO.

Easiest solution man is to MARK the water level with a marker or tape or something.

Then just re-fill it everyday to that level.

I don't stress about it too much.

Unless you have over 150G the evap should be less than a gallon a day, which in that size is not causing any huge salinity swings.

Just dont let it go on too long before checking.

Exhibit A.

Excellent. Thanks!! It's time to pull out the sharpie (or tape). I'm glad something in this hobby can be easy and inexpensive. LOL

 

[terraincognita]

Excellent. Thanks!! It's time to pull out the sharpie (or tape). I'm glad something in this hobby can be easy and inexpensive. LOL

HAHAHA!

RIGHT!

Actually that's a shot from my 10G Nano.

I've only spent $250-$300 on equipment for that tank. Including the tank, lighting, and all rocks and sand etc. (For the last week I've successfuly started growing SPS as well)

Probably $500 on live stock -.-........ dang COVID.

But depending on your tank schedules, maintenance, and habits, you don't HAVE to spend all the money on equipment.

each tank is super individual.

 

[Karen00]

Salinity is set by mixing a measured amount of salt in a particular amount of water. The salt never leaves the tank but the water evaporates. Adding back new water to the same volume brings the water back to the same salinity.
How fast the water evaporates depends on room temperature and humidity and changes from summer to winter.

None of the other components of your salt mix like Ca or MG will evaporate either but their levels will change because they are used by animals in your tank and other factors.

Aaah... Thank you!! That clarifies it (the usage of the other elements by the livestock but salt isn't). It totally makes sense now. Thanks again!!

I think I now have a complete picture of water chemistry and maintaining it. This was the one thing holding me back from taking the plunge. I think I'm ready to jump. I really appreciate all the replies to this thread!

 

[terraincognita]

Aaah... Thank you!! That clarifies it (the usage of the other elements by the livestock but salt isn't). It totally makes sense now. Thanks again!!

I think I now have a complete picture of water chemistry and maintaining it. This was the one thing holding me back from taking the plunge. I think I'm ready to jump. I really appreciate all the replies to this thread!

This playlist while it's not the most in-depth into every detail in the hobby.

It's the most comprehensive from A-Z of what you need to know to be successful in the hobby.

Watching a few episodes a week will do you lots of good.

I've watched the whole series 2-3 times.

 

[Karen00]

HAHAHA!

RIGHT!

Actually that's a shot from my 10G Nano.

I've only spent $250-$300 on equipment for that tank. Including the tank, lighting, and all rocks and sand etc. (For the last week I've successfuly started growing SPS as well)

Probably $500 on live stock -.-........ dang COVID.

But depending on your tank schedules, maintenance, and habits, you don't HAVE to spend all the money on equipment.

each tank is super individual.

Most excellent!! I'm glad to know this is a nano! That's about the size I'm looking to start with. I know starting small can be harder for noobs because of water chemistry but I'm squeezed for space at the moment which makes a nano ideal and why I wanted to be sure I was crystal clear in managing the water. Do you just keep corals or fish and others as well? That was my next area of focus... Livestock. I figured I could start cycling the tank while I sort out what can be kept in a 10g.

 

[Karen00]

This playlist while it's not the most in-depth into every detail in the hobby.

It's the most comprehensive from A-Z of what you need to know to be successful in the hobby.

Watching a few episodes a week will do you lots of good.

I've watched the whole series 2-3 times.

Sweet, thanks!! I will start on this right away!

 

[Steve Elb]

Thank you for the ATO suggestion. I just started googling this subject but was getting a little overwhelmed by all of the different ones out there (like most of the equipment needed I suppose). Haha.

Tunze osmolator!